The present invention relates to radio communication system and mobile communication station used for a communication system.
Heretofore, as it is disclosed in the official gazette of Japanese Patent Kokai-Koho Kai 2000-49690, in order to substantially expand a communicable area by restraining a rise of system costs, a portable telephone set has been known to the public. The portable telephone set comprises a normal reception unit, a normal transmitting unit, an inputting means, a reception unit, a transmission unit, and a control unit. The normal reception unit receives communication information at normal communication times as a portable telephone set; and the normal transmitting unit transmits the communication information at normal times. The inputting means inputs at least a propriety of setting communication for outside area and the reception unit is for outside area to receive and detect an area outside code. The transmission unit is for area outside to transmit the communication information at area out time. Additionally, the control unit performs a system control of the control unit. This mobile telephone set performs a normal communication of a reception information to its local station with a calling side in case it is located in the communicable area with a base station. However, in cases when the reception information is not to the local station, the mobile telephone set performs a relay operation by attaching a relay code. And in cases in which the mobile telephone set is located in area outside capable of communicating with the base station, the reception information to the self station performs a normal communication by attaching an area outside code with the calling side. Finally, in cases where it is not the reception information communicated to the self station, the mobile telephone set performs a relay operation with the area outside by attaching a relay code.
In the conventional portable telephone relay system, the existing communicable area can be expanded without bringing about an increase of the existing base stations. However, the presence of the base station is indispensable, and costs for installation of the facilities is expensive. Additionally, the increased cost gives rise to a burden of the costs to the subscribers. Furthermore, at an emergency time, call concentration upon a specific base station tends to cause an inability to communicate.
An object of the present invention is to solve the foregoing problems.